block: vhdx - add .bdrv_create() support

This adds support for VHDX image creation, for images of type "Fixed"
and "Dynamic".  "Differencing" types (i.e., VHDX images with backing
files) are currently not supported.

Options for image creation include:
    * log size:
        The size of the journaling log for VHDX.  Minimum is 1MB,
        and it must be a multiple of 1MB. Invalid log sizes will be
        silently fixed by rounding up to the nearest MB.

        Default is 1MB.

    * block size:
        This is the size of a payload block.  The range is 1MB to 256MB,
        inclusive, and must be a multiple of 1MB as well.  Invalid sizes
        and multiples will be silently fixed.  If '0' is passed, then
        a sane size is chosen (depending on virtual image size).

        Default is 0 (Auto-select).

    * subformat:
        - "dynamic"
            An image without data pre-allocated.
        - "fixed"
            An image with data pre-allocated.

        Default is "dynamic"

When creating the image file, the lettered sections are created:

-----------------------------------------------------------------.
|   (A)    |   (B)    |    (C)    |     (D)       |     (E)
|  File ID |  Header1 |  Header 2 |  Region Tbl 1 |  Region Tbl 2
|          |          |           |               |
.-----------------------------------------------------------------.
0         64KB      128KB       192KB           256KB          320KB

.---- ~ ----------- ~ ------------ ~ ---------------- ~ -----------.
|     (F)     |     (G)       |    (H)    |
| Journal Log |  BAT / Bitmap |  Metadata |  .... data ......
|             |               |           |
.---- ~ ----------- ~ ------------ ~ ---------------- ~ -----------.
1MB         (var.)          (var.)      (var.)

Signed-off-by: Jeff Cody <jcody@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

1 files changed, 14 insertions, 1 deletions

diff --git a/block/vhdx.h b/block/vhdx.h
index f222d1876e..51183b243c 100644
--- a/block/vhdx.h
+++ b/block/vhdx.h
@@ -18,6 +18,11 @@
 #ifndef BLOCK_VHDX_H
 #define BLOCK_VHDX_H
 
+#define KiB              (1 * 1024)
+#define MiB            (KiB * 1024)
+#define GiB            (MiB * 1024)
+#define TiB ((uint64_t) GiB * 1024)
+
 /* Structures and fields present in the VHDX file */
 
 /* The header section has the following blocks,
@@ -36,8 +41,9 @@
 #define VHDX_HEADER1_OFFSET         (VHDX_HEADER_BLOCK_SIZE * 1)
 #define VHDX_HEADER2_OFFSET         (VHDX_HEADER_BLOCK_SIZE * 2)
 #define VHDX_REGION_TABLE_OFFSET    (VHDX_HEADER_BLOCK_SIZE * 3)
+#define VHDX_REGION_TABLE2_OFFSET   (VHDX_HEADER_BLOCK_SIZE * 4)
 
-
+#define VHDX_HEADER_SECTION_END     (1 * MiB)
 /*
  * A note on the use of MS-GUID fields.  For more details on the GUID,
  * please see: https://en.wikipedia.org/wiki/Globally_unique_identifier.
@@ -55,6 +61,7 @@
 /* These structures are ones that are defined in the VHDX specification
  * document */
 
+#define VHDX_FILE_SIGNATURE 0x656C696678646876  /* "vhdxfile" in ASCII */
 typedef struct VHDXFileIdentifier {
     uint64_t    signature;              /* "vhdxfile" in ASCII */
     uint16_t    creator[256];           /* optional; utf-16 string to identify
@@ -85,6 +92,7 @@ typedef struct QEMU_PACKED MSGUID {
 /* The full header is 4KB, although the actual header data is much smaller.
  * But for the checksum calculation, it is over the entire 4KB structure,
  * not just the defined portion of it */
+#define VHDX_HEADER_SIGNATURE 0x64616568
 typedef struct QEMU_PACKED VHDXHeader {
     uint32_t    signature;              /* "head" in ASCII */
     uint32_t    checksum;               /* CRC-32C hash of the whole header */
@@ -125,6 +133,7 @@ typedef struct QEMU_PACKED VHDXHeader {
 } VHDXHeader;
 
 /* Header for the region table block */
+#define VHDX_REGION_SIGNATURE  0x69676572  /* "regi" in ASCII */
 typedef struct QEMU_PACKED VHDXRegionTableHeader {
     uint32_t    signature;              /* "regi" in ASCII */
     uint32_t    checksum;               /* CRC-32C hash of the 64KB table */
@@ -238,6 +247,7 @@ typedef uint64_t VHDXBatEntry;
 #define VHDX_METADATA_MAX_ENTRIES 2047  /* not including the header */
 #define VHDX_METADATA_TABLE_MAX_SIZE \
     (VHDX_METADATA_ENTRY_SIZE * (VHDX_METADATA_MAX_ENTRIES+1))
+#define VHDX_METADATA_SIGNATURE 0x617461646174656D  /* "metadata" in ASCII */
 typedef struct QEMU_PACKED VHDXMetadataTableHeader {
     uint64_t    signature;              /* "metadata" in ASCII */
     uint16_t    reserved;
@@ -267,6 +277,8 @@ typedef struct QEMU_PACKED VHDXMetadataTableEntry {
                                                    If set indicates a fixed
                                                    size VHDX file */
 #define VHDX_PARAMS_HAS_PARENT           0x02    /* has parent / backing file */
+#define VHDX_BLOCK_SIZE_MIN             (1   * MiB)
+#define VHDX_BLOCK_SIZE_MAX             (256 * MiB)
 typedef struct QEMU_PACKED VHDXFileParameters {
     uint32_t    block_size;             /* size of each payload block, always
                                            power of 2, <= 256MB and >= 1MB. */
@@ -274,6 +286,7 @@ typedef struct QEMU_PACKED VHDXFileParameters {
                                            the rest are reserved (see above) */
 } VHDXFileParameters;
 
+#define VHDX_MAX_IMAGE_SIZE  ((uint64_t) 64 * TiB)
 typedef struct QEMU_PACKED VHDXVirtualDiskSize {
     uint64_t    virtual_disk_size;      /* Size of the virtual disk, in bytes.
                                            Must be multiple of the sector size,